Automatic fluid delivery devices are well known. Typically, a force acts on a container holding a fluid so that the fluid, which is usually highly viscous, e.g., pastes, oils, medicaments, and the like, is disposed out of an end of the container. A spring or gas is typically used to supply the force acting on the container.
Known from patent EP-B-0 435 512 is a medicament delivery device in which a spring provided in the interior of a container directly acts on a plunger which separates the spring portion from the medicament portion. Due to the force of the spring the plunger is pushed into the medicament portion to dispel the medicament. Through an infusion tube the medicament is transported to the treatment site in the human body. The flow of the medicament is opened and closed by a clamp attached to the infusion tube. Any other way of closing off the medicament flow is achievable only at significantly greater expense.
U.S. Pat. No. 4,874,368, and PCT application WO 93/06940 describe delivery devices which deliver fluids from two containers arranged in parallel. The containers each have a movable plunger on one end, and an orifice on the other. Each plunger is connected to a plunger rod, the rods being held by a cover containing them. By manually moving the cover in the direction of the contained materials, the two plungers are pushed uniformly in the direction of the contained materials, disposing the materials out of the containers through the orifices. A dual cannula is fitted to the two orifices of the containers, and acts to mix the two materials upon discharge.
The disadvantage of these known devices is that the force for delivering the fluids dispensed needs to be applied either manually or, where automatic fluid delivery is involved, the device is insufficient for a dispensed delivery.